He said: "There was no announcement in any party manifesto, no Green Paper, no statement in the Queen's Speech.

"And yet here we are on the verge of primary legislation.

"From a democratic point of view, it's a shambles.

"George Orwell would be proud of that manoeuvre. I think the process is shambolic."

Speaking to the congregation at Westminster Cathedral during Christmas Eve mass, Archbishop Nichols said: "Sometimes sexual expression can be without the public bond of the faithfulness of marriage and its ordering to new life.

"Even governments mistakenly promote such patterns of sexual intimacy as objectively to be approved and even encouraged among the young."

The government is confident of getting a bill, set to be introduced in January, through the Commons and the Lords - however it may have to rely on the Labour Party to secure its passage.